Regarding W-CDMA (Wideband Code Division Multiple Access), LTE (Long Term Evolution), and LTE-A (LTE-Advance) which are standards for mobile communication, it has been considered to introduce a small radio base station Home (e)Node B for the purposes of expansion of service areas, individual use, and the like. Regarding the Home (e)NB, a UE (User Equipment) which is allowed to access the base station can be limited. The base station subjected to the limitation is referred to as a CSG (Closed Subscriber Group). The standardization of this CSG has been in process by 3GPP (3rd Generation Partnership Project).
Hereinafter, the 3GPP standard regarding the CSG is explained.
An owner or operator of the CSG can freely set the allowance or forbiddance of access to the CSG for each mobile station device. Additionally, the owner or operator can set a period of time for which the mobile station device is allowed to access the CSG (hereinafter, accessible time). The accessible time is managed on the network side, and is not reported to the mobile station device (see Non-Patent Document 2). After the accessible time expires, the mobile station device is not allowed to camp on the CSG cell. Further, it is defined by the standard of the 3GPP Rel-8 that if communication is in process when the accessible time expires, the communication call is forced to be disconnected (see Non-Patent Document 1 and 3).
If information concerning the allowance or forbiddance of access to the CSG is changed, the changed information is reported to the mobile station device. Based on the reported information, an allowed CSG list stored by the mobile station device is updated. However, the detailed procedure of updating the allowed CSG list has not yet been defined by the 3GPP.
Whether to allow or forbid access to the CSG is determined when the mobile station device detects a CSG cell, based on the following three steps.
Step 1: The mobile station device obtains CSG identification information (CSG identity) reported by system information of the CSG cell.
Step 2: The mobile station device confirms whether or not the received CSG identification information is included in the allowed CSG list stored by the mobile station device.
Step 3: If the allowed CSG list is included, the mobile station device determines that access to the CSG cell is allowed. If the allowed CSG list is not included, the mobile station device determines that access to the CSG cell is not allowed.